Real nice gains!

For the exhaust tone being to loud for you, not really much you can do..you achieved these gains by making the engine breath better..every part that was installed added to the pitch of the exhaust..

What you could do(page out of a ricer book), is install a set of exhaust tip silencers, you'll see them on kids with civics cruising with 4.5-5" exhaust tips(there will be a insert in the tip)..get a extra set of muffler extensions made to the bumper tips, get the silencer tube installed in the new extensions and have them fitted in place when you want the tone a bit lower..swap the extensions when you want it louder..saves on the weight of putting the OEM muffler in place and takes less time to swap out (something you can do in 10mins with a 13mm deep socket and racket)..it's a thought that would work..cost of material would be around +/-50$

 

Irish, does this page out of the ricer book give you a ricer look? Any pics you could share that shows what you're talking about?

 

No ricer look on the idea I've described, I can refer to a exhaust tip silencer for a random car..but kind of the same idea ..found on on ebay, http://www.ebay.ca/itm/BMW-525i-325i...item45ff979b00

Normally this whole thing would get put inside the exhaust tip..this size would not fit though(way to large), for what I described..this idea would need to be made up by a exhaust shop or someone with the right tools ..on the OEM muffler, there is extensions from the muffler that align behind the rear bumper exhaust tips.. these extensions would need to be made into a silencer, you can even insulate it with fiberglass to better deaden the sound..For the aftermarket V8/12V and DB9 mufflers I know some don't have extensions, so the ends will need to be cut and flared..then the cut off pipe section would be the new extension that would be clamped to the muffler pipe..have 2 little extra pipes made for when you don't want the silencers in place


The silencer pipe is pretty much turning the muffler extensions into little mufflers and shrinking the final output pipe size(which combined lower sound)...when you want the exhaust back to loud, take the silencer extenions off and fit the reguler extensions ..like I stated before, would take 5-10mins..once you get the hand of it , even less than 5mins ..13mm deep 3/8 and rachet, loosen pipe clamp, slide out extension silencer and fit in place extension pipe..secure clamp and done..

There would be no visual change from looking outside nor underneith, you would have to get on the ground and look about 6 inchs into the exhaust pipe to see the silencer inside the extension pipe ...I've done this myself on mustang's in the past to go for inspects after ppl got pulled over by cops for noise pullution..same idea

 

Hi CJ:
Great job on all the work you did to discover the real hp gains by installing the cats. I just bought an AMV8 and I was thinking of doing the RSC ECU and the cats, and leave the stock mufflers in. So... how does the story ends?... Did you re-installed the OEM mufflers or you kept the loud set-up?
On another note... I don't know why people put so much attention to the weight they take off when they change the mufflers.. Actually, after owning four Porsches 911 (and racing them for 16 years), having a little weight in the back is good!!! It helps with traction going in and out of corners and it balances the car when braking. The weight in the back allows less transfer of weight to the front axle (dive), leaving the steering wheels light and not having to deal with the extra weight. This makes the entry and exit of a corner flatter and with less drama. That is why, 911s brake flat at corner entry, and you can punch them out at the exit without reservations. If one takes too much weight out of the back of a car (35 lbs. is a lot to take off), it will unbalance the car's weight transfer from which the suspension was set-up initially... Just my two cents!

Hope to hear from you!!!

 

Hi RP: As I said before, I just bought a 2007 AMV8. Thinking of doing RSC ECU and cats. Do you happen to have a video of how your cats with the stock mufflers sound??? It would be a big help for me... Thanks!

 

No problem, bunch of the people on the forums wanted it so I found a shop that could install and run dynos. It sounds about right that the 911 has a lot of junk in the trunk, glad you're racing the Vantage (I don't have the ***** to race my precious Aston Martin).

As far as the noise, I should have updated everyone a while ago. It really toned down a bit, and I got used to it. It still has that distinct bouncing rev noise of a standard Aston Martin, just louder and growlier. With the windows down, it doesnt bother me at all. The drone on the highway is something I will experience this weekend if it doesnt rain on Friday, I will drive my car up to my apt in Philly and keep it with me all weekend. Regardless I am keeping my approx. 440hp

 

CJ, do you have a plot of your AFRs from the dyno pulls?

 

Yes please refer to post #39 in this thread.

 

i saw the dyno charts, but they don't include AFRs. did you have them measure it while you were on the dyno?

 

Cj: Glad to hear that you finally are happy with the sound of your set-up. Congratulations on the gains too!!! You did a wonderful job on enlighteing us about the topic. Probably, the sound toned down because of the accumulation of carbon particles inside the walls of the unit(s), buffering the sound a little but, it must sound deeper and with more bass at around 120Hz. I'm not racing the Aston. I retired from racing about 2 years ago. After, 22 years of doing it, it was enough. Also at 47 years young, one starts to lose reaction time, and reflexes, not to mention eyesight. Who knows... the bug might bite me later again... Thank you, again!

 

I'm sorry I guess I didn't understand what AFRs meant. If you can explain what you are looking for I can see if the shop measured that. I don't think gave me anything else besides what I posted on Post #39.

That is interesting. Also, maybe the warmer weather has helped? Either way its toned down a bit from when I first had it put on. I would recommend this setup for anyone that finds having just an aftermarket exhaust is a bit quiet unless you're really revving. Or anyone that needs the extra power and can live with a car thats slightly louder then one might want.

Further, I think some exhausts are a bit louder with this setup (Tubi to name one).

 

Telum-see post #31 shows power gain and AFR changes pre and post CATs. AFR is much leaner and very close to where you want it to be to get max power.

https://www.6speedonline.com/forums/...s-today-3.html

And yes Racer X, I already know

 

Haha, I wasn't going to say anything, I swear!

 

hahaha, too funny. I wonder how much the leaner AFR (versus the stock that falls off a cliff) helps the power?

 

no worries, thanks for all the info you're posting

awesome, thank you. i'm running a bit more rich than that... i started a new thread to fix my mess so i don't clog up everyone else's threads haha

https://www.6speedonline.com/forums/...lp-please.html